Materials science in the far-IR with electrostatic based FELs

Abstract A technology gap exists between ∼ 100 GHz and ∼ 10 THz. Free-electron lasers (FELs), driven by high quality, relatively low energy electron beams from electrostatic accelerators, and capable of generating kilowatts of coherent, tunable radiation, are ideally suited to explore the enabling science for future technology in this spectral range. We describe two experiments that use terahertz “optical rectification” to measure i) the intensity and temperature dependent energy relaxation in quantum wells and ii) the intrinsic relaxation of resonant tunneling diodes. Both benefit from the power and tunablilty of the UCSB FELs.